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12th December, 2018


Springtime Snowdrops

The month of February has brought longer days, emergence of snowdrops and a green carpet of grass as one travels the countryside. The winter to date has been relatively mild, which has had a positive effect on the demand for scarce feed reserves.

Stocks for silage have been exhausted on many farms. The transport of bales of silage is an industry in itself. The quality of a lot of baled and pit silage is very poor with DMD’s close to 60. Many farmers have avoided the supplementation of this silage with the required concentrates to maintain body condition score (BCS) in the dry cow period.

Focus primarily on maintaining the BCS in the dry cow period. It is worth noting that 80pc of the future production potential of the dairy herd is dependent on management in the transition period. This encompasses the eight week pre and two week period post calving.

Supplementary concentrates with good quality minerals and vitamins is money well spent for cows in the transition period as BCS is the primary determining factor for future health and reproductive performance. With the calving season now in full tilt, the rearing of newborn calves has to begin with colostrums management. It is not alone essential to get the required quantity and quality into the calf as soon as possible after birth, but also important to avoid the batch feeding of colostrum.

Colostrum is the primary source of Johne’s disease

Colostrum is the primary source of Johne’s disease. This disease is caused by Mycobacterium Avium Paratuberculosis (MAPS), which results in poor thrive and death of cattle. Unfortunately, MAPS has been isolated from humans with Crohn’s disease. There is, therefore, the need to remove the risk of transmission and the association with a human health condition.

Johne’s disease can be identified by milk samples taken from individual cows at the time of milk recording. However, further testing will be required using dung samples to get a definitive assessment of true positive for the disease in the herd. A major difficulty with MAPS has been the identification of the disease in young animals.

It is interesting to note that mature cows identified with the disease will not alone have daughters positive to MAPS but also herd mates born around the same time. This has arisen because of the bulk feeding of colostrums to all newborn calves. In the USA and continental Europe, many dairy units have resorted to the pasteurization of colostrums to avoid the transmission of the disease. This works successfully but requires an initial capital investment of €5,000. An alternative is to feed calves colostrums individually from non-infected cows and then put the calves on milk replacer.

An example of a cow with Johnes Disease

Johne’s disease is a significant cause of impaired performance on many dairy and suckler herds. Unfortunately, many farmers are unaware of the extent of the disease. Cows with the disease will have impaired reproductive performance and will be culled on this basis before clinical symptoms in terms of diarrhoea and loss of body condition are expressed.

Any form of stress in the herd will exacerbate expression of Johne’s disease. Therefore, if your herd is losing body condition because of poor silage quantity and quality and failure to feed a good quality supplementary concentrate, the immune system of your cows will be challenged. This will increase the risk of clinical cases of Johne’s disease.

Animal Health Ireland plan to implement an eradication programme for Johne’s, which is welcome. Biosecurity is an integral element in control. Many continental beef cattle were imported as foundation females over the past ten years. These have been a source of the disease transmission in Ireland.

In conclusion, BCS has to be managed properly to avoid loss in the dry cow period and no more than 0.5 BCS loss in the first six weeks post calving. Colostrum management has to entail the avoidance of bulk feeding of same as the risk of transmission of Johne’s disease is greatest through colostrums.

Dr. Dan Ryan is a bovine reproductive physiologist and can be contacted at  
More details about Johnes Disease are available on our blog Johnes Disease-Explained